add unused assignment checker

aptos-labs · Jun 4, 2024 · be23cd9 · be23cd9
1 parent beab1a5
commit be23cd9
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Showing 4 changed files with 25 additions and 0 deletions.
diff --git a/third_party/move/move-compiler-v2/src/experiments.rs b/third_party/move/move-compiler-v2/src/experiments.rs
@@ -141,6 +141,11 @@ pub static EXPERIMENTS: Lazy<BTreeMap<String, Experiment>> = Lazy::new(|| {
             description: "Whether to check for unused struct type parameters".to_string(),
             default: Inherited(Experiment::CHECKS.to_string()),
         },
+        Experiment {
+            name: Experiment::UNUSED_ASSIGNMENT_CHECK.to_string(),
+            description: "Whether to check for unused assignments".to_string(),
+            default: Inherited(Experiment::CHECKS.to_string()),
+        },
         Experiment {
             name: Experiment::VARIABLE_COALESCING.to_string(),
             description: "Whether to run variable coalescing".to_string(),
@@ -215,6 +220,7 @@ impl Experiment {
     pub const SPLIT_CRITICAL_EDGES: &'static str = "split-critical-edges";
     pub const UNINITIALIZED_CHECK: &'static str = "uninitialized-check";
     pub const UNUSED_STRUCT_PARAMS_CHECK: &'static str = "unused-struct-params-check";
+    pub const UNUSED_ASSIGNMENT_CHECK: &'static str = "unused-assignment-check";
     pub const USAGE_CHECK: &'static str = "usage-check";
     pub const VARIABLE_COALESCING: &'static str = "variable-coalescing";
     pub const VARIABLE_COALESCING_ANNOTATE: &'static str = "variable-coalescing-annotate";

diff --git a/third_party/move/move-compiler-v2/src/lib.rs b/third_party/move/move-compiler-v2/src/lib.rs
@@ -34,6 +34,7 @@ use crate::{
         uninitialized_use_checker::UninitializedUseChecker,
         unreachable_code_analysis::UnreachableCodeProcessor,
         unreachable_code_remover::UnreachableCodeRemover, variable_coalescing::VariableCoalescing,
+        unused_assignment_checker::UnusedAssignmentChecker,
     },
 };
 use anyhow::bail;
@@ -391,6 +392,11 @@ pub fn bytecode_pipeline(env: &GlobalEnv) -> FunctionTargetPipeline {
         pipeline.add_processor(Box::new(UninitializedUseChecker { keep_annotations }));
     }
 
+    if options.experiment_on(Experiment::UNUSED_ASSIGNMENT_CHECK) {
+        pipeline.add_processor(Box::new(LiveVarAnalysisProcessor::new(false)));
+        pipeline.add_processor(Box::new(UnusedAssignmentChecker {}));
+    }
+
     // Reference check is always run, but the processor decides internally
     // based on `Experiment::REFERENCE_SAFETY` whether to report errors.
     pipeline.add_processor(Box::new(LiveVarAnalysisProcessor::new(false)));

diff --git a/third_party/move/move-compiler-v2/src/pipeline/mod.rs b/third_party/move/move-compiler-v2/src/pipeline/mod.rs
@@ -23,6 +23,7 @@ pub mod split_critical_edges_processor;
 pub mod uninitialized_use_checker;
 pub mod unreachable_code_analysis;
 pub mod unreachable_code_remover;
+pub mod unused_assignment_checker;
 pub mod variable_coalescing;
 pub mod visibility_checker;
 

diff --git a/third_party/move/move-compiler-v2/tests/testsuite.rs b/third_party/move/move-compiler-v2/tests/testsuite.rs
@@ -145,6 +145,18 @@ const TEST_CONFIGS: Lazy<BTreeMap<&str, TestConfig>> = Lazy::new(|| {
             dump_bytecode: DumpLevel::None,
             dump_bytecode_filter: None,
         },
+        TestConfig {
+            name: "unused-assignment",
+            runner: |p| run_test(p, get_config_by_name("unused-assignment") ),
+            include: vec!["/unused-assignment/"],
+            exclude: vec![],
+            exp_suffix: None,
+            options: opts.clone().set_experiment(Experiment::UNUSED_ASSIGNMENT_CHECK, true),
+            stop_after: StopAfter::BytecodePipeline(Some("UnusedAssignmentChecker")),
+            dump_ast: DumpLevel::None,
+            dump_bytecode: DumpLevel::EndStage,
+            dump_bytecode_filter: None,
+        },
         // Tests for lambda lifting
         TestConfig {
             name: "lambda-lifting",